The world of technology has been loaded with the field of IoT or the Internet of things. IoT has changed our way of seeing the world and work ethics. It’s been a part of every technology around us including consumer electronics and industrial devices.

The SIM800 from both Arduino and SimCom has gained immense popularity recently because of the great support from the community of developers and technicians. 

Connecting to the Internet, sending emails, texting, and calling all occurred through cellular communication. This cellular communication device is known as SIM800. This module basically functions as a smartphone but needs an external connection to work properly. The SIM800 possesses so many qualities and features. 

SIM800 helps you in creating innovative projects if it is connected to Arduino. SIM800 is not only good at making projects but is also a very viable and affordable choice to use as a communication module in various types of devices.

Consideration:

The following mentioned benefits and disadvantages help you in understanding whether it is the best option to choose for the project or not.

Pros:

1. The biggest pro of SIM800 is that it is supported and recommended by many experienced and skilled technicians and developers.
2. It has amazing features for texting, calling, and internet access.
3. It comes in small sizes which makes it perfect to use in consumer devices especially wearable and portable ones. 
4. It is affordable and cheap, especially when it is bought from Chinese manufacturers.
5. Many manufacturers like SimCom also provide SIM800 with other communication modules. Built-in GPS is one of those amazing features.

Cons:

1. One of the biggest drawbacks is that it only comes with a limited 2G data speed. Moreover, the GPS has also been phased out many times in many areas.
2. Regardless of being small, affordable, and high-performance, it’s only used for cellular modules generally.

Warning:

The GSM and GPS cellular module in SIM800 only works in specific phases and it is phased out in most regions which is why it is especially not a recommended choice for modern designs.

Programming & Prototyping for SIM800C ARDUINO

Basic Connections

The connection between SIM800 and Arduino for general communication links is quite simple. You just need three lines between Arduino and SIM800. These contain receive and send lines of ground UART.

After that, put the SIM card inside the SIM800 module. Connect the RX and TX SIM800 with D7 and D8 Arduino respectively. These provide a communication link between different modules and are called serial UART links or connections. 

Also always ensure that the SIM800 sending pin connects with the Arduino receiver pin and the SIM800 receiving pin connects with Arduino sending pin. 

Arduino uses 5V while SIM800 is not able to tolerate 5V which is why the level logic it uses is 3.3V. This shows that the D7 Arduino signal has to step down to a SIM800 logic level of 3.3V so that it won’t get damaged. Various methods are available but using a resistor divider is one of the simplest and easiest ways. 

After that link, the antenna with the mini socket is placed in the top left area of SIM800.

Power Supply For SIM800C ARDUINO

3.7V is the standardized power supply to the SIM800 among various cellular modules. People might consider using the 3.3V and 5V supply which is really not recommended. The SIM800’s tolerance of power supply is between 3.4 and 4.3 volts. Therefore, using 5 voltage power supply could damage the module while 3.3-voltage is not considered enough for a reliable connection. 

That is why an external polymer battery with a voltage of 3.7V is utilized as an external power source. Generally, for the best result, a decoupling power-generating circuit is put into the supply of input. 

· Serial Monitor:

A serial monitor provides interference with Arduino while communicating with SIM800. It is also used for checking the current state of the appliance. Moreover, it is also used to send commands for communicating with Arduino.

· Simple Serial communication:

The code is used to create a communication link between Arduino and SIM800. First of all, a set of pins generates a simple serial communication connection between both devices. Then set the rate of buad up to 9600.

During the looping of code, SIM800 constantly waits to get any input signals from the serial monitor. It then sends the input signals to SIM800 using the D7 pin. It also constantly reads the pin D8 in case the SIM800 sends any responses back.

Once the Arduino is connected to the device like a PC, the setup is completed. Compile serial communication code and then upload it on Arduino. Since the basic serial connection is established, there is also another way to communicate with SIM800 through the monitor by transferring AT commands. AT command is a type of command key specially created to perform the desired operations on SIM800. The code is sent to Arduino which relays the message to SIM800 to perform.

“AT” is one of the basic commands anyone can use. When “AT” is typed on the serial monitor “AT” comes in the response. This ensures that Arduino has a perfect communication link with the SIM800 module.

· Downloading Web Page:

The SIM800 module has a remarkable ability to download web pages from the Internet. This can easily be done by putting an AT command on the serial monitor.

First of all, ensure the quality of signals. Since SIM800 is an old version so there might be a chance of not getting proper internet signals. Therefore check the quality of the signal by putting the command “AT+CSQ”. This is not used to create a strong internet connection. However, it might help in monitoring the level of signals during the debugging process.

After establishing and checking the internet connection then comes up creating a web session by setting an environment of the browser. First of all, the HTTP setting is being placed. Then put the URL of the website you want to download. The command relays to the SIM800 module and makes it download the website page. Once all the data on the web page is downloaded. You can easily access all the content by using a serial monitor.

What Else Can You Do With The SIM800C ARDUINO?

The SIM800 module can easily be integrated into consumer, miniature, and portable devices, especially wearable gadgets. SIM800 module and the Arduino are also widely used in making automation systems for homes, GPS trackers, and wireless sensor remotes. 

· Low-cost Weather Forecast

One of the simplest uses of the SIM800 module and Arduino is creating a weather forecasting gadget, especially for farmers at low cost. This project used colors to provide weather forecasts for almost 10 days. 

The device is designed to locate the user’s current location and then download the weather details from a famous weather forecasting platform called Weather Underground. One of the biggest features of the SIM800 module is to identify the current location of this device. It does not give an as accurate location as GPS can give but for such a simple device, a rough estimate would be enough.

· GSM Antenna

Antenna can be added to the device and product in two ways by utilizing the SIM800 module. It can be added either by using an SMA connector or a mini Radio-frequency coax connector. The Radio-Frequency interface contains 50 ohms impedance. However, this impedance also matches the trace resistance of the antenna. 

Designing Radio-Frequency traces for the antenna of the SIM800 module is a quite complex process. Therefore, for design, you need expert guidance and advice so that there won’t be any mistakes. For better results and avoid unwanted mistakes then follow the design guidelines of the manufacturer.

Conclusion

The SIM800 module is an ideal choice for creating a 2G cellular communication link in consumer devices or the projects’ products. It is small, affordable, easy to handle, cheaper, and has a friendly user interface through the monitor, and commanding ability makes it ideal among many developers and manufacturers. Since it is ideal for many reasons, it gained popularity and is supported by various technicians and developers. It is widely available around the market and can easily be found.